This invention relates generally to manual battery chargers and more particularly, but not necessarily exclusively, to chargers for lead-acid batteries of the type commonly found in motor vehicles.
A majority of batteries that are used in automobiles are lead-acid batteries of a flooded design. These batteries are very rugged and can survive a substantial amount of abuse, including that resulting from overcharging. Sealed lead-acid batteries often are flooded batteries with large electrolyte reservoirs and one or more caps configured to recombine gasses and to return the recombined gasses to the reservoirs. In this manner, the amount of gasses lost to the atmosphere due to overcharging is limited. When helping to start a car with a weak battery using crank assist, many commercial garages take advantage of the overcharge resistance of such batteries by increasing the amount of current put into the battery to help recharge the battery and help the battery in starting the vehicle.
Newer types of sealed batteries on the market today, including absorbent glass mat (AGM) and gel cells do not require periodic watering, but do require that they be charged in a more precise manner to limit the amount of gasses that can still escape from these batteries and to prevent explosions. In addition, voltages must be limited to avoid damage to vehicle electronics and monitoring systems.
Many battery chargers in use or on the market today are manually controlled. For example, a manual battery charger may be connected to a battery, plugged in to a source of AC power, and turned on to charge a connected battery. The manual battery charger simply supplies a current to the battery that tapers off as the battery voltage increases. Although such a manual battery charger is adequate for flooded lead acid batteries, they are not adequate to provide the controlled charging of newer types of sealed batteries, or to avoid damage to vehicle electronics and monitoring systems when a battery still connected to a vehicle is being charged.
It would thus be desirable to provide apparatus and methods adequate for charging newer types of sealed batteries and to avoid damage to vehicle electronics and monitoring systems while reducing the cost of same by continuing to utilize existing manually controlled battery chargers.